The present invention relates to fastening parts suitable for recycling, and fixing structures of electronic equipment that use these parts. Throughout the world, concerns are growing regarding the destruction of the environment on a global scale. With the amount of waste increasing each passing year, efforts are underway to recycle waste as well as to reduce the amount of waste being generated. These efforts are also being undertaken with such electronic equipment as information processing devices. To ensure that resources are used more effectively, the complete or partial recycling of such devices is already being attempted.
The service life of electronic equipment is based on the durability of the product (measured in expected years of use) and the frequency with which the product is used. Although a given device may be nearing the end of its service life, many of its components may still have many years of use left in them. These components need to be targeted for reuse or recycling. More specifically, electronic equipment, such as personal computers and printers, contain numerous plastic and metal parts. These parts are considered appropriate recycling targets.
Electronic parts, like printed circuit boards, are generally fixed to mold-formed plastic housings. First, a metal insert with a threaded hole (screw seat) is inserted into the cavity of a boss on the housing for integration as one unit. Then the electronic part is mounted on the boss and the screw is tightened in the screw seat of the metal insert.
In a prior art, a metal insert with the screw seat is formed simultaneously as one unit with the plastic housing during a plastic forming operation. According to another method, after the plastic housing is molded, the metal insert is set into the boss by applying pressure with supersonic waves.
Another type of assembly setup makes use of the characteristics of springs. With this assembly setup, after the molding process, the metal insert is snapped in position on the boss so that the boss covers the insert. For all assembly setup types, however, the metal insert is fixed to the boss of the plastic housing. It is therefore difficult to separate or remove the metal insert from the plastic housing.
See FIG. 1 for an example of a conventional structure. FIG. 1 shows a metal insert 6 with a screw seat (threaded hole) molded as one unit in the boss of a plastic housing 2. Also, an annular groove 8 is formed beforehand in the circumference of the boss 4 to facilitate the removal of the metal insert 6.
For disassembly, dedicated tools are used to bend and remove the boss 4 (with metal insert 6) from the housing 2. This bending and removing process tends to weaken the fastening part, and creates difficulties in identifying the metal insert 6. As a result, the process becomes time consuming and laborious.
For recycling plastics, it is necessary to design products that can be easily disassembled for recycling. The plastic housing of electronic equipment should be designed without the use of metal inserts. Note that from the point of view of certain functions, however, the use of metal inserts is unavoidable.
Electronic equipment is usually disassembled at the end of its service life. In recycling the plastic and disassembled parts of electronic equipment, many steps are required to separate and remove the metal inserts in conventional structures. This complicates the recycling process.
What is required to resolve these problems includes structures that are easily disassembled and separated (i.e., structures from which metal inserts are easily separated and removed). Thus, one of the objectives of the present invention is to offer fastening parts with metal inserts suitable for recycling.
Another objective of the present invention is to offer a fixing structure for electronic equipment suitable for recycling. The fastening parts with metal inserts are easily separated and removed from plastic housings.
The present invention provides fastening parts suitable for recycling, characterized by a plastic main body with at least two engaging projections for connection with a cooperating member, such as a housing for electronic equipment, or the like, and metal inserts with an interior screw thread integrally inserted in the plastic main body. The plastic main body preferably possesses a conical or pyramid-trapezoidal shape. Otherwise, the plastic main body may be composed of a square-shaped lower part and a cylindrical upper part. The plastic main body can be formed of ABS resin or polypropylene, for example.
The present invention additionally provides a fixing structure for electronic equipment characterized by a plastic housing suitable for recycling with a boss formed with through-holes, a plastic main body having at least two engaging projections inserted in the through-holes of the boss, a fastening part composed of metal inserts with interior screws integrally inserted in the main body, an electronic part having a through-hole mounted on the boss, and a screw passing said through-hole mounted and engaged in the fastening part.
By providing the fastening part with a conical or pyramid-trapezoidal shape, tightening the screw firmly causes the fastening part to come into firm contact with the interior surface of the boss in order to prevent relative rotation between the fastening part and the boss.
The boss which receives the fastening part is formed with multiple grooves for holding the engaging projections. When the fastening part is inserted into a through-hole of the boss, each engaging projection on the fastening part engages a cooperating groove of the boss, thereby allowing the fastening part to be temporarily fixed inside the boss.
When the fastening part is composed of a square-shaped lower part and a cylindrical upper part, the through-hole of the boss should be stepped to accommodate the shape of the fastening part.
In use, loosening the screw in damaged electronic equipment separates the fastening part from the housing whereby the fastening part can be reused. The fastening part, which has a metal insert, can be easily separated from the plastic housing. Thus, if the housing is melted and then formed again, the plastic can be recycled and reused.